Trapping of a magnetic flux in granular YBa$_2$Cu$_3$O$_{7-\delta}$ high-temperature superconductors under the action of an external magnetic field and transport current
Abstract:
Magnetic flux trapping (MFT) in granular YBa$_2$Cu$_3$O$_{7-\delta}$ high-temperature superconductors (HTSCs) is studied. At $T$ = 77.36 K, the dependence of the hysteresis of the transverse magnetoresistance on transport current $I$ and the maximum value of external magnetic field $H_{\mathrm{ext}}$ is found in the measurement cycle $0\to H^{\mathrm{max}}_{\mathrm{ext}}\to 0$. The dependences of the parameters characterizing MFT, namely, residual magnetoresistance, field $H_{\mathrm{min}}$ at which the magnetoresistance is minimal, and the magnetoresistance at $H_{\mathrm{ext}}=H_{\mathrm{min}}$, on $I$ and $H^{\mathrm{max}}_{\mathrm{ext}}$ are determined. MFT is found to occur in HTSC granules under the action of an external magnetic field exceeding the lower critical field of superconducting granules $H_{\mathrm{c1A}}$, and the transport current only weakly affects the magnitude of MFT.
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